Illinois regulators say hair smoothing products used by salons may produce harmful formaldehyde, even if the ingredient isn't listed on labels.
The Illinois Department of Financial and Professional Regulation is warning salons to use high-risk products carefully.
Formaldehyde has been found in salons in other states that used Brazilian Blowout Acai Professional Smoothing Solution and Professional Brazilian Blowout Solution.
Product labels may list the formaldehyde under another name or say "formaldehyde-free" because of the way the ingredient reacts.
Salon professionals can be exposed during the hair straightening process, especially when heat is applied.
Regulators say formaldehyde can irritate the eyes and nose, cause allergic reactions of the skin, and is linked to cancer of the nose and lung.